The present embodiments relate to a lifting device for adjusting the height of a top part relative to a base part for a patient couch (e.g., support, table, or stretcher).
Lifting devices of this kind are known from the prior art and are used for the vertical positioning of a patient couch or a patient table. The top part and the base part are usually embodied in the form of panels or frames which can be moved relative to each other by an elevator mechanism, thereby resulting in a height adjustment of the top part relative to the base part.
A suitable elevator mechanism for a lifting device is, for example, a simple scissor mechanism. A simple scissor mechanism is a paired embodiment of two levers which cross each other at a scissor pivot joint. The two “scissors” are configured in parallel with each other and move synchronously. Each of these “scissors” is mounted on the top part and the base part at two support points in each case. A simple scissor mechanism is characterized by a high degree of stiffness due to the large distances between the support points on the top part and base part. In the case of a limited length of the top part or of the base part, however, a simple scissor construction cannot be moved very far down due to the lever ratios.
Alternatively, a dual or multiple scissor mechanism may be provided. In the case of a dual or multiple scissor mechanism, two or more “scissors” are configured one above the other. The lowermost of the scissors is mounted on the base part and the uppermost on the top part at two support points in each case. Such a scissor mechanism is likewise embodied in a paired manner. Provision is made for two parallel constructions of “scissors” which are configured one above the other, such that four support points are actually formed on the top part and on the base part respectively.
When comparing a dual-scissor mechanical arrangement with a simple scissor mechanism, given the same length of the top part and of the base part, the dual-scissor mechanical arrangement may be contracted further downward. As a result of the short distances between the support points, however, the dual-scissor arrangement has a lower degree of stiffness than a simple scissor mechanism.